An accelerometer is a sensor which detects/measures acceleration due to gravity and/or an applied force (e.g., from physical motion). Such devices have numerous applications in the automotive, consumer products, and other industries. Although various accelerometer configurations are known, capacitive accelerometers (which detect/measure acceleration by converting a capacitance change into a proportional voltage) are popular due to their relatively low power and noise, their relatively high sensitivity, and their relatively small device footprint.
While accelerometers are now in widespread use, they may suffer from one or more drawbacks such as cross-axis sensitivity. Cross-axis sensitivity is the output detected on one axis (the sensing axis) of an accelerometer that is due to acceleration imposed on another axis (e.g., an orthogonal axis, which may also be referred to as the cross direction). The percentage cross-axis sensitivity is often expressed as a ratio of the measured sensitivity in the cross direction to the measured sensitivity in the sensing direction.
As noted above, capacitive accelerometers convert a detected change in capacitance to a proportional voltage that is representative of the acceleration of a proof mass. With such designs, cross-axis sensitivity can cause a capacitance change to be detected in one axis when acceleration is occurring along another axis of the accelerometer, potentially resulting in sensing errors. Indeed as cross axis sensitivity increases, the relative accuracy of an accelerometer may decrease. Many current commercial grade accelerometers have relatively high (≥2%) cross axis sensitivity, which may make them unsuitable for high precision applications. Although cross-axis sensitivity may be reduced by using several accelerometers in parallel, such an approach may undesirably increase the cost of the device. Hence, the development of new accelerometer designs that address the cross-axis sensitivity issue remain of interest.